Apparatus and method for reducing power consumption in portable terminal

ABSTRACT

An apparatus and a method for reducing power consumption in a portable terminal that transmits digital broadcast data through an ad hoc network are provided. If a terminal receiving digital broadcast transmits the received digital broadcast to a neighboring terminal, a control unit enters a sleep mode after buffering received data for a predefined time.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of a prior applicationSer. No. 14/329,290, filed on Jul. 11, 2014, which will issue as U.S.Pat. No. 9,924,461 on Mar. 20, 2018, which is a continuation of priorapplication Ser. No. 12/969,767, filed on Dec. 16, 2010, which hasissued as U.S. Pat. No. 8,805,317 on Aug. 12, 2014, and which claimedthe benefit under 35 U.S.C § 119(a) of a Korean patent application filedon Dec. 21, 2009 in the Korean Intellectual Property Office and assignedSerial number 10-2009-0127813, the entire disclosures of each are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and a method for reducingpower consumption in a portable terminal that transmits digitalbroadcast data through an ad hoc network. More particularly, the presentinvention relates to an apparatus and a method for buffering receiveddata in a portable terminal and transmitting the buffered data aftermaintaining a sleep state for a predefined time.

2. Description of the Related Art

Recently, portable terminals have become necessities to many peoplewithout distinction of age and gender, and service providers andterminal manufacturers are competitively developing products (orservices) for differentiation from other enterprises.

For example, portable terminals have evolved into multimedia devicesthat can provide various functions and services including any or all ofphone book functions, game functions, a Short Message Service (SMS), anElectronic (E)-mail services, morning call functions, Motion PictureExpert Group Audio Layer-3 (MP3) functions, scheduling functions,digital camera functions, multimedia message services, wireless Internetservices, and the like.

WiFi terminals with a wireless Local Area Network (LAN) function haverecently been released. The WiFi terminals with a wireless LAN functionare used to access e-mail, Web and string media. WiFi provides awireless broadband Internet access service to users, thus making itpossible to rapidly and conveniently access an on-line network duringmovement as well as at home and office.

The WiFi network may be divided into an ad hoc network, which providesdirect communication between WiFi terminals without passing through anAccess Point (AP), and an infra network based on the AP.

When a terminal with a digital broadcast receiving module and terminalswithout a digital broadcast receiving module are connected through an adhoc network to each other, the terminal with a digital broadcastreceiving module transmits broadcast data to the terminals without adigital broadcast receiving module, thereby enabling the sharing of thedigital broadcast.

Because the ad hoc network does not provide an AP, each of the terminalsgenerates/transmits a beacon notifying the existence of a network. Whenapproaching the Target Beacon Transmission Time (TBTT), the terminalsgenerate a beacon after a random delay time.

That is, the terminals wake up at the TBTT to monitor a physical channelof the ad hoc network for a random delay time set in each terminal. Theterminal immediately cancels the beacon transmission if another terminalgenerates a beacon before it transmits a beacon.

When a beacon interval starts, the terminals wake up for an AnnouncementTraffic Indication Message (ATIM) window interval to transmit a beaconframe. If there is data communication between transmitting/receivingterminals, the terminals must maintain a wake-up state. On the otherhand, if there is no data communication between thetransmitting/receiving terminals, the terminals enter a sleep mode forthe remaining interval except an ATIM window in the beacon interval,thus minimizing the power consumption.

As described above, if the terminal receives a TeleVision (TV) channelthrough an ad hoc network and immediately retransmits the same to areceiving terminal, it continuously receives several mixed broadcastchannels. Therefore, if the broadcast data are retransmitted thoroughWiFi, there is no period to stop the operation of a receiver.Accordingly, it cannot enter a sleep mode until the completion oftransmission of digital broadcast data, thereby increasing the powerconsumption.

Therefore, a need exists for an apparatus and a method for reducingpower consumption in a portable terminal that transmits digitalbroadcast data through an ad hoc network.

SUMMARY OF THE INVENTION

An aspect of the present invention is to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages below. Accordingly, an aspect of the present invention isto provide an apparatus and a method for reducing power consumption in aportable terminal that transmits digital broadcast data through an adhoc network.

Another aspect of the present invention is to provide an apparatus and amethod for reducing power consumption in a portable terminal byincreasing a sleep period when retransmitting data through an ad hocnetwork.

Another aspect of the present invention is to provide an apparatus and amethod for reducing the number of times of performing a periodic wake-upoperation for monitoring an Announcement Traffic Indication Message(ATIM) frame in a portable terminal when there is no data communicationbetween transmitting/receiving terminals.

In accordance with an aspect of the present invention, an apparatus forreducing power consumption in a portable terminal connected through anad hoc network is provided. The apparatus includes a control unit forentering a sleep mode after buffering received data for a predefinedtime, if a terminal receiving digital broadcast transmits the receiveddigital broadcast to a neighboring terminal.

In accordance with another aspect of the present invention, a method forreducing power consumption in a portable terminal connected through anad hoc network is provided. The method includes entering a sleep modeafter buffering received data for a predefined time, if a terminalreceiving digital broadcast transmits the received digital broadcast toa neighboring terminal.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspect, features, and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a block diagram of a portable terminal that minimizes powerconsumption by increasing a sleep period when retransmitting datathrough an ad hoc network according to an exemplary embodiment of thepresent invention;

FIG. 2 is a diagram illustrating a process for transmitting digitalbroadcast data in a portable terminal according to an exemplaryembodiment of the present invention;

FIG. 3 is a flowchart illustrating a process for transmitting digitalbroadcast data in a portable terminal according to an exemplaryembodiment of the present invention;

FIG. 4 is a flowchart illustrating a process for setting an adaptivebeacon interval in a portable terminal according to an exemplaryembodiment of the present invention;

FIG. 5 is a flowchart illustrating a process for preoccupying a beaconafter transmission of buffered data in a portable terminal according toan exemplary embodiment of the present invention;

FIG. 6A is a diagram illustrating a process for transmitting digitalbroadcast data in a portable terminal according to an exemplaryembodiment of the present invention;

FIG. 6B is a diagram illustrating a process for setting an adaptivebeacon interval in a portable terminal according to an exemplaryembodiment of the present invention; and

FIG. 6C is a diagram illustrating a process for preoccupying a beaconafter transmission of buffered data in a portable terminal according toan exemplary embodiment of the present invention.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention is provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to those ofskill in the art, may occur in amounts that do not preclude the effectthe characteristic was intended to provide.

Exemplary embodiments of the present invention provide an apparatus anda method for reducing power consumption in a portable terminal byincreasing a sleep period when retransmitting data through an ad hocnetwork. Exemplary embodiments of the present invention also provide anapparatus and a method for reducing the number of times of performing aperiodic wake-up operation for monitoring an Announcement TrafficIndication Message (ATIM) frame in a portable terminal when there is nodata communication between transmitting/receiving terminals.

FIGS. 1 through 6C, discussed below, and the various exemplaryembodiments used to describe the principles of the present disclosure inthis patent document are by way of illustration only and should not beconstrued in any way that would limit the scope of the disclosure. Thoseskilled in the art will understand that the principles of the presentdisclosure may be implemented in any suitably arranged communicationssystem. The terms used to describe various embodiments are exemplary. Itshould be understood that these are provided to merely aid theunderstanding of the description, and that their use and definitions inno way limit the scope of the invention. Terms first, second, and thelike are used to differentiate between objects having the sameterminology and are in no way intended to represent a chronologicalorder, unless where explicitly state otherwise. A set is defined as anon-empty set including at least one element.

FIG. 1 is a block diagram of a portable terminal that minimizes powerconsumption by increasing a sleep period when retransmitting datathrough an ad hoc network according to an exemplary embodiment of thepresent invention.

Referring to FIG. 1, a portable terminal may include a control unit 100,a beacon generating unit 102, a memory unit 106, an input unit 108, adisplay unit 110, and a communication unit 112. The beacon generatingunit 102 may include an adaptive beacon interval setting unit 104. Theportable terminal may include additional units that are not illustratedhere merely for the sake of clarity. Similarly, the functionality of twoor more of the above units may be integrated into a single component.

The control unit 100 of the portable terminal controls an overalloperation of the portable terminal. For example, the control unit 100processes and controls voice communication and data communication. Inaddition to the typical functions, according to an exemplary embodimentof the present invention, the control unit 100 minimizes powerconsumption when retransmitting digital broadcast data through an ad hocnetwork, by setting a target delay time for transmission ofretransmission data and buffering/transmitting data for only a portionof the set time while maintaining a sleep state for the remaining time.

In addition, after transmitting the buffered data, the control unit 100generates an adaptive beacon interval prior to transmission in order toreduce power consumption caused by a wake-up operation in an ATIMwindow.

Herein, the adaptive beacon interval denotes the interval indicating theATIM frame nonexistence interval among the retransmission datatransmission time except the buffered data transmission interval, whichcorresponds to the data transmission interval minus the buffered datatransmission time. Accordingly, after detecting the adaptive beaconinterval, portable terminals may enter a sleep mode by determining thatthere is no ATIM frame for the adaptive beacon interval.

Herein, the control unit 100 may set the adaptive beacon intervalimmediately after transmitting buffered data or at the time whenpreoccupying a beacon after transmission of the buffered data.

The beacon generating unit 102 generates a beacon corresponding to aframe for notifying the existence of a network or performing a networkmaintenance function. According to an exemplary embodiment of thepresent invention, the beacon generating unit 102 generates a beaconincluding the adaptive beacon interval. That is, the beacon generatingunit 102 generates a beacon including the adaptive beacon interval setby the adaptive beacon interval setting unit 104, so that portableterminals enter a sleep mode due to the nonexistence of the ATM frame.

The adaptive beacon interval setting unit 104 generates an adaptivebeacon interval, which represents the ATIM frame nonexistence intervalamong the retransmission data transmission time except the buffered datatransmission interval, and provides the same to the beacon generatingunit 102. Herein, the control unit 100 may set the adaptive beaconinterval immediately after transmitting buffered data or at the timewhen the portable terminal preoccupies a beacon after transmission ofthe buffered data.

The memory unit 106 may include any or all of a Read Only Memory (ROM),a Random Access Memory (RAM) a flash ROM, and the like. The ROM stores avariety of reference data and microcodes of a program for the processand control of the control unit 100 and the beacon generating unit 102.

The RAM is a working memory of the control unit 100, which storestemporary data that are generated during the execution of variousprograms. The flash ROM stores a variety of updatable data, such as aphone book, an outgoing message, an incoming message, and the like.

The input unit 108 includes numeric keys of digits 0-9 and a pluralityof function keys, such as a Menu key, a Cancel (delete) key, aConfirmation key, a Talk key, an End key, an Internet connection key,Navigation keys (or Direction keys), character input keys, and the like.The input unit 108 provides the control unit 100 with key input datathat corresponds to a key pressed by a user.

The display unit 110 may display any or all of numerals and characters,moving pictures, still pictures, status information generated during anoperation of the portable terminal, and the like. The display unit 110may be a color Liquid Crystal Display (LCD), an Active Mode OrganicLight Emitting Diode (AMOLED), and the like. If the display unit 110 hasa touch input device and is applied to a touch input type portableterminal, it can be used as an input device.

The communication unit 112 transmits/receives Radio Frequency (RF)signals inputted/outputted through an antenna (not illustrated). Forexample, in a transmitting (TX) mode, the communication unit 112channel-encodes, spreads and RF-processes TX data prior to transmission.In a receiving (RX) mode, the communication unit 112 converts a receivedRF signal into a baseband signal and despreads and channel-decodes thebaseband signal to restore the original data. According to an exemplaryembodiment of the present invention, the communication unit 112transmits/receives a beacon including the adaptive beacon interval.

The control unit 100 of the portable terminal may also be configured toperform the functions of the beacon generating unit 102. Althoughseparate units are provided for respective functions of the control unit100, the control unit 100 may also be configured to perform all or someof the functions on behalf of such separate units.

FIG. 2 is a diagram illustrating a process for transmitting digitalbroadcast data in the portable terminal according to an exemplaryembodiment of the present invention.

Referring to FIG. 2, a portable terminal buffers received data andtransmits the buffered data after maintaining a sleep state for apredefined time, in order to reduce power consumption caused by thetransmission of data without a sleep mode.

When the portable terminal transmits received data (205) to terminalsconnected through an ad hoc network, it sets a target delay timecorresponding to a retransmission data transmission time. Herein, thetarget delay time denotes the interval for transmission of the buffereddata after the buffering of the data for a predefined time in order tosolve the problem of the need to perform a wake-up operation because itcontinuously transmits the digital broadcast data at a low data rate.

Accordingly, the portable terminal buffers (201) and transmits (203) theretransmission data for a portion of the target delay time and enters asleep mode for the remaining time, thereby minimizing the powerconsumption.

FIG. 3 is a flowchart illustrating a process for transmitting digitalbroadcast data in a portable terminal according to an exemplaryembodiment of the present invention.

Referring to FIG. 3, a portable terminal transmits digital broadcastdata through an ad hoc network to terminals incapable of receivingdigital broadcast, and retransmits digital broadcast data of a specificchannel whose retransmission is requested by a receiving terminal.According to an exemplary embodiment of the present invention, whentransmitting the digital broadcast data, the portable terminal uses aportion of the target delay time as a data buffering time and enters apower saving mode for the remaining time except the buffered datatransmission interval, thereby reducing the power consumption.

In step 301, the portable terminal connects to neighboring portableterminals through an ad hoc network. In step 303, the portable terminalreceives a data retransmission request from a receiving terminal sharingthe digital broadcast data with the portable terminal. Herein, the dataretransmission request denotes a request that causes a terminal,incapable of receiving digital broadcast data, to receive digitalbroadcast and transmits the received data to other portable terminals.

In step 305, the portable terminal detects data information to beretransmitted. In step 307, the portable terminal sets a target delaytime corresponding to a retransmission data transmission time. Herein,the target delay time denotes the interval (i.e., the data transmissiontime) for transmission of the buffered data after the buffering of thedata for a predefined time in order to solve the problem of the need toperform a wake-up operation because it continuously transmits thedigital broadcast data at a low data rate.

If the portable terminal sets the data transmission time to be long,there is an increase in the delay between a transmitting terminal and areceiving terminal, thus inconveniencing the user viewing digitalbroadcast. Therefore, the portable terminal sets the data transmissiontime according to the characteristics of digital broadcast. That is, theportable terminal may set the data transmission time to be short in thecase of broadcast, such as news, and may increase the data transmissiontime up to the buffering allowable capacity level in the case ofbroadcast channels, such as movies that is not sensitive to delay. Inaddition, when retransmitting time-slice transmitted Digital VideoBroadcasting—Handheld (DVB-H) data, the portable terminal may transmit amovie channel in an increased data transmission interval without theneed to set the data transmission time in a predefined data transmissioninterval (Delta-T).

In step 309, the portable terminal enters a sleep mode for the datatransmission time set in step 307 and stops data transmission, in orderto reduce power consumption caused by a continuous wake-up operationduring the data retransmission.

In step 311, for a predefined time, the portable terminal buffersdigital broadcast data to be transmitted to the receiving terminalrequesting the data retransmission. In step 313, the portable terminaldetermines whether the buffering of the digital broadcast data hascompleted. That is, in step 313, the portable terminal determineswhether a predefined time for buffering the digital broadcast data hasexpired. When retransmitting the digital broadcast data, a conventionalportable terminal must perform a continuous wake-up operation. However,the portable terminal, according to an exemplary embodiment of thepresent invention, maintains a sleep state and wakes up for a predefinedtime to buffer the digital broadcast data.

If it is determined in step 313 that the buffering of the digitalbroadcast data has not completed, the portable terminal returns to step311 to again perform a digital broadcast data buffering operation.

In contrast, if it is determined in step 313 that the buffering of thedigital broadcast data has completed, the portable terminal proceeds tostep 315. In step 315, the portable terminal transmits the buffereddata. In step 317, the portable terminal determines whether the datatransmission time set in step 307 has expired.

If it is determined in step 317 that the data transmission time has notexpired, the portable terminal proceeds to step 321 to enter a sleepmode and then returns to step 317. That is, when transmitting thedigital broadcast data, the portable terminal wakes up for only aportion of the predefined data transmission time to buffer/transmit datato be retransmitted and enters a sleep mode for the remaining time,thereby reducing the power consumption.

In contrast, if it is determined in step 317 that the data transmissiontime has expired, the portable terminal proceeds to step 319. In step319, the portable terminal determines whether the data transmission hascompleted.

If it is determined in step 319 that the data transmission has notcompleted, the portable terminal returns to step 303.

In contrast, if it is determined in step 319 that the data transmissionhas completed, the portable terminal ends the algorithm.

FIG. 4 is a flowchart illustrating a process for setting an adaptivebeacon interval in a portable terminal according to an exemplaryembodiment of the present invention.

Referring to FIG. 4, an adaptive beacon interval denotes the intervalindicating the ATIM frame nonexistence interval among the retransmissiondata transmission time (described with reference to FIG. 3) except thebuffered data transmission interval, which corresponds to the datatransmission interval minus the buffered data transmission time. Ifthere is no data communication between transmitting/receiving terminals,the portable terminal reduces the power consumption by reducing thenumber of times of performing a periodic wake-up operation formonitoring an ATIM frame.

In step 401, the portable terminal determines whether the transmissionof the data, the retransmission of which is requested by the receivingterminal, has completed.

If it is determined in step 401 that the data transmission has notcompleted, the portable terminal again performs step 401.

In contrast, if it is determined in step 401 that the data transmissionhas completed, the portable terminal proceeds to step 403. In step 403,the portable terminal determines whether a beacon is preoccupied. Thatis, in step 403, the portable terminal determines whether the portableterminal transmitting the data beforehand generates a beacon.

If it is determined in step 403 that a beacon is not preoccupied, theportable terminal proceeds to step 413 to perform other function (e.g.,an operation of receiving a beacon generated by other terminal).

In contrast, if it is determined in step 403 that a beacon ispreoccupied, the portable terminal proceeds to step 405. In step 405,the portable terminal determines the adaptive beacon interval. Theadaptive beacon interval denotes the ATIM frame nonexistence intervalamong the data transmission time except the buffered data transmissioninterval, which corresponds to the data transmission interval minus thebuffered data transmission time.

In step 407, the portable terminal generates a beacon including theadaptive beacon interval determined in step 405. In step 409, theportable terminal transmits the beacon generated in step 407.

During the adaptive beacon interval, by using the beacon including theadaptive beacon interval, the portable terminals determines that thereis no data transmission between transmitting/receiving terminals, andenters a sleep mode without periodically waking up for monitoring theATIM frame, thereby reducing the power consumption.

In step 411, the portable terminal determines whether it corresponds toan adaptive beacon interval.

If it is determined in step 411 that the portable terminal correspondsto an adaptive beacon interval, the portable terminal proceeds to step415 to enter a sleep mode by determining that there is no datatransmission between the transmitting/receiving terminals, and returnsto step 411.

In contrast, if it is determined in step 411 that the portable terminaldoes not correspond to an adaptive beacon interval, the portableterminal proceeds to step 319 of FIG. 3 to determine whether the datatransmission has completed.

FIG. 5 is a flowchart illustrating a process for preoccupying a beaconafter transmission of buffered data in a portable terminal according toan exemplary embodiment of the present invention.

Referring to FIG. 5, a portable terminal sets an adaptive beaconinterval by preoccupying a beacon upon completion of buffered datatransmission, thereby minimizing the power consumption.

In step 501, the portable terminal determines whether the transmissionof the data, the retransmission of which is requested by the receivingterminal, has completed.

If it is determined in step 501 that the data transmission has notcompleted, the portable terminal again performs step 501.

In contrast, if is determined in step 501 that the data transmission hascompleted, the portable terminal proceeds to step 503. In step 503, theportable terminal sets a random delay before the generation of a beaconafter a Target Beacon Transmission Time (TBTT) is set as a minimum. Step503 is performed so that the portable terminal preoccupies a beacon uponcompletion of buffered data transmission to transmit the adaptive beaconinterval. That is, the portable terminal removes an ATIM window intervalfor ATIM frame monitoring by allocating a minimum random delay valuebefore beacon transmission so that the portable terminal can preoccupy aphysical channel at the end time point of the buffering datatransmission.

Accordingly, the end time point of the adaptive beacon intervalcorresponds to the time to retransmit buffered data after the end of theprevious data transmission time.

In step 505, the portable terminal preoccupies a beacon and returns tostep 405 of FIG. 4.

FIGS. 6A through 6C are diagrams illustrating a process for reducingpower consumption in a portable terminal according to an exemplaryembodiment of the present invention.

FIG. 6A is a diagram illustrating a process for transmitting digitalbroadcast data in a portable terminal according to an exemplaryembodiment of the present invention.

Referring to FIG. 6A, while a conventional portable terminal mustperform a continuous wake-up operation when retransmitting digitalbroadcast data, a portable terminal, according to an exemplaryembodiment of the present invention, buffers the retransmission data foronly a portion of the data transmission time and enters a sleep mode forthe remaining time, thereby minimizing the power consumption.

That is, after transmitting the buffered data, the portable terminalrepeats a process of waking up an ATIM window for a beacon interval andentering a sleep mode for the remaining period, thereby reducing thepower consumption.

FIG. 6B is a flow diagram illustrating a process for setting an adaptivebeacon interval in a portable terminal according to an exemplaryembodiment of the present invention.

Referring to FIG. 6B, in order to minimize power consumption, a portableterminal reduces the number of times of performing a periodic wake-upoperation for monitoring an ATIM frame, if there is no datacommunication between transmitting/receiving terminals, during theinterval among the data transmission time except the buffered datatransmission interval.

That is, in order to reduce the power consumption caused by a wake-upoperation in an ATIM window, if the portable terminal preoccupies abeacon (601), it sets a periodic adaptive beacon interval indicating thenonexistence of an ATIM frame (605), and then generates/transmits abeacon including the adaptive beacon interval. Herein, the portableterminal generates an adaptive beacon interval, which corresponds to thedata transmission interval minus the buffered data transmission time, toreduce the number of times of performing a periodic wake-up operationfor monitoring the ATIM frame.

Herein, the end time point of the adaptive beacon interval correspondsto the time to retransmit buffered data after the end of the previousdata transmission time. If the portable terminal does not preoccupy thebeacon, it periodically wakes up to monitor the ATIM frame. As comparedto the case of FIG. 6A, the portable terminal can reduce the powerconsumption by entering a sleep mode after preoccupying the beacon.

FIG. 6C is a flow diagram illustrating a process for preoccupying abeacon after transmission of buffered data in a portable terminalaccording to an exemplary embodiment of the present invention.

Referring to FIG. 6C, a portable terminal prevents a periodic wake-upoperation from being performed to monitor an ATIM frame, in the periodwhere the beacon is not preoccupied in FIG. 6B.

That is, the portable terminal sets an adaptive beacon interval (609) bypreoccupying a beacon (607) immediately after the transmission ofbuffered data. When determining that the transmission of the data, theretransmission of which is requested by a receiving terminal, iscompleted, the portable terminal sets a minimum random delay before thegeneration of a beacon after a TBTT to preoccupy a beacon, thus removingan ATIM window period where the portable terminal wakes up to monitor anATIM frame.

As described above, exemplary embodiments of the present inventionprovide an apparatus and a method for reducing power consumption in aportable terminal by increasing a sleep period when retransmitting datathrough an ad hoc network. Exemplary embodiments of the presentinvention also provide an apparatus and a method for reducing the numberof times of performing a periodic wake-up operation for monitoring anATIM frame in a portable terminal when there is no data communicationbetween transmitting/receiving terminals. Accordingly, exemplaryembodiments of the present invention can reduce power consumption in aportable terminal caused by the continuous transmission ofretransmission data without a sleep state.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. An apparatus comprising: a memory; an antenna; acommunication unit operatively coupled with the antenna and adapted totransmit a signal to an external electronic device using the antenna viaa wireless local network; and a control unit operatively coupled withthe communication unit, the control unit adapted to: operate in a firststate during a first portion of a specified period of time, theoperating in the first state including transmitting, using thecommunication unit, at least one portion of multimedia data stored inthe memory to the external electronic device via the wireless localnetwork continuously during the first portion of the specified period oftime, and operate in a second state during a second portion of thespecified period of time immediately after an elapse of the firstportion, the operating in the second state including transmitting, usingthe communication unit, time information indicative of a length of thespecified period of time to the external electronic device via thewireless local network during at least one subportion of the secondportion of the specified period of time and refraining from transmittinga portion of the multimedia data to the external electronic device viathe wireless local network during the second portion of the specifiedperiod of time.
 2. The apparatus of claim 1, wherein the control unit isfurther adapted to: transmit the at least one portion of the multimediadata from the apparatus directly to the external electronic device. 3.The apparatus of claim 1, wherein the control unit is further adaptedto: as at least part of the operating in the first state, operate in awake-up state during the first portion.
 4. The apparatus of claim 3,wherein the control unit is further adapted to: as at least part of theoperating in the second state, operate in a sleep state during anothersubportion of the second portion immediately after the elapse of thefirst portion and before the at least one subportion.
 5. The apparatusof claim 4, wherein the control unit is further adapted to: as at leastpart of the operating in the second state, operate in the wake-up stateduring a third subportion of the second portion immediately after theelapse of the other subportion and before the at least one subportionwithout transmitting a portion of the multimedia data or a portion ofthe time information.
 6. The apparatus of claim 5, wherein the controlunit is further adapted to: as at least part of the operating in thesecond state, operate in the sleep state during a fourth subportion ofthe second portion immediately after the elapse of the third subportionand immediately before the at least one subportion.
 7. The apparatus ofclaim 1, wherein the control unit is further adapted to: as at leastpart of the operating in the second state, operate in the sleep stateduring another subportion of the second portion immediately after theelapse of the at least one subportion and until an end of the secondportion.
 8. The apparatus of claim 1, wherein the control unit isfurther adapted to: as at least part of the operating in the secondstate, buffer another portion of the multimedia data during the secondportion of the specified period of time.
 9. The apparatus of claim 8,wherein the control unit is further adapted to: operate in the firststate during a first portion of another iteration of the specifiedperiod of time immediately after the elapse of the second portion, theoperating in the first state during the first portion of the otheriteration including transmitting the other portion of the multimediadata buffered during the second portion to the external electronicdevice via the wireless local network during the first portion of theother iteration of the specified period of time.
 10. The apparatus ofclaim 1, wherein the control unit is further adapted to: determine thespecified period of time based at least in part on a characteristic ofthe multimedia data.
 11. The apparatus of claim 1, wherein the controlunit is further adapted to: transmit the time information to theexternal electronic device as at least part of a beacon.
 12. Anapparatus comprising: a memory; an antenna; a communication unitoperatively coupled with the antenna and adapted to transmit a signal toan external electronic device using the antenna via a wireless localnetwork; and a control unit operatively coupled with the communicationunit, the control unit adapted to: operate in a first state during afirst portion of a specified period of time period, the operating in thefirst state including transmitting, using the communication unit, atleast one portion of data stored in the memory to the externalelectronic device via the wireless local network continuously during thefirst portion of the specified period of time, and operate in a secondstate during a second portion of the specified period of timeimmediately after an elapse of the first portion, the operating in thesecond state including: refraining from transmitting a portion of thedata during the second portion of the specified period of time,transmitting, using the communication unit, a beacon including timeinformation to be used for communication between the apparatus and theexternal electronic device to the external electronic device via thewireless local network during a first subportion of the second portionof the specified period of time, and operating in a sleep state during asecond subportion of the second portion immediately after the elapse ofthe first subportion.
 13. The apparatus of claim 12, wherein the controlunit is further adapted to: determine the specified period of time basedat least in part on a characteristic of the data.
 14. The apparatus ofclaim 12, wherein the control unit is further adapted to: as at leastpart of the operating in the first state, operate in a wake-up stateduring the first portion.
 15. The apparatus of claim 12, wherein thecontrol unit is further adapted to: buffer another portion of the dataduring the second portion of the specified period of time.
 16. Theapparatus of claim 15, wherein the control unit is further adapted to:operate in the first state during a first portion of another iterationof the specified period of time immediately after the elapse of thesecond portion, the operating in the first state during the firstportion of the other iteration including transmitting the other portionof the data buffered during the second portion to the externalelectronic device via the wireless local network during the firstportion of the other iteration of the specified period of time.
 17. Anapparatus comprising: a memory; an antenna; a communication unitoperatively coupled with the antenna and adapted to transmit a signal toan external electronic device using the antenna via a wireless localnetwork; and a control unit operatively coupled with the communicationunit, the control unit adapted to: transmit, using the communicationunit, at least one portion of data stored in the memory to the externalelectronic device via the wireless local network during a portion of aspecified period of time, refrain from transmitting a portion of thedata or a beacon to the external electronic device via the wirelesslocal network during a first subportion of a remaining portion of thespecified period of time immediately after an elapse of the portion ofthe specified period of time, and transmit, using the communicationunit, at least one beacon to the external electronic device via thewireless local network during a second subportion of the remainingportion of the specified period of time after the elapse of the firstsubportion, wherein the control unit is further adapted to refrain fromtransmitting at least one portion of the data to the external electronicdevice via the wireless local network during the second subportion. 18.The apparatus of claim 17, wherein the control unit is further adaptedto: determine the specified period of time based at least in part on acharacteristic of the data.
 19. The apparatus of claim 17, wherein thecontrol unit is further adapted to: buffer another portion of the dataduring the remaining portion of the specified period of time.
 20. Theapparatus of claim 17, wherein the control unit is further adapted to:operate in a sleep state during a third subportion of the remainingportion of the specified period of time immediately after the elapse ofthe second subportion and until an end of the remaining portion.